Place the flour in a bowl and make a well in the center.

Warm 250 ml of milk. Crumble the yeast into the well, add 50 g of sugar and 100 ml of lukewarm milk. Mix with a bit of flour from the edge to form a thick batter.

Cover the pre-dough and let it rise in a warm place for about 15 minutes.

Then add butter, 1 egg, 50 g sugar, 1 pinch of salt, and 150 ml of lukewarm milk. Knead with the dough hooks of a hand mixer until smooth.

Cover the dough and let it rise until it has doubled in size, about 30 minutes.

Wash, trim, and quarter the strawberries. Wash and trim the rhubarb, cutting it into pieces about 1.5 cm long. Mix rhubarb with 1 tablespoon of sugar.

Briefly knead the yeast dough again and roll it out on a floured work surface to a rectangle (about 41 x 32 cm).

Grease the baking tray and place the dough on it. Cover and let it rise in a warm place for 10-15 minutes.

Mix crème fraîche, vanilla sugar, 5 eggs, pudding powder, and 150 ml of milk together.

Distribute strawberries and rhubarb on the cake, pouring the custard over the top.

Bake in a preheated oven (electric: 200 °C / fan: 175 °C / gas: level 3) for 20-30 minutes.

Remove the cake from the oven and let it cool. Cut into pieces. Best served slightly warm or at room temperature.